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Want to add new features to your old Mac? The Mac ROM-inator II replaces the stock Macintosh ROM with a programmable flash memory module. Add a bootable ROM disk, change the startup chime, hack the icons, gain HD20 support and get a 32-bit clean ROM. The Mac ROM-inator supports the Macintosh IIx, IIcx, IIci, IIfx, IIsi, and SE/30.

The Mac ROM-inator II is fully assembled and ready to use. Just plug it in and go.

The Mac ROM-inator II is great for breathing new life into your old II-series Mac or SE/30. Customized startup sounds and icons add a touch of fun, and the ROM disk provides fast and convenient boot-ups. The flash ROM comes pre-programmed with a custom ROM image with the following changes as defaults:

The pre-programmed ROM image is compatible with the Macintosh IIx, IIcx, IIci, IIfx, IIsi, and SE/30. The Mac ROM-inator II module is physically compatible with any Macintosh having a 64-pin ROM SIMM socket, except the Quadra 660AV and 880AV. This includes the previously mentioned models as well as many other Quadra, LC, and Performa models. For these other models, the flash memory will need to be reprogrammed with an appropriate ROM image.

Some SE/30 hardware may require a SIMM shim to ensure ideal fit – see instructions for details. SE/30 computers running Mac OS System 7.5 or later require a software patch.

For a similar ROM upgrade for the Macintosh Plus, 512Ke, 512K, and 128K, see the original Mac ROM-inator Kit.

HD20 Support and 32-Bit Clean ROM

A nice benefit of the pre-programmed ROM image is to add built-in support for HD20-type hard disks, such as the HD20 hard disk emulation mode of the BMOW Floppy Emu. The Macintosh IIx, IIcx, IIfx, and SE/30 lack HD20 support in their stock ROMs, so this replacement ROM enables those machines to use HD20 disks.

The pre-programmed ROM image also makes the Mac 32-bit clean, enabling it to use more than 8MB of RAM natively without the need for special system enablers or extensions. Some older Macintosh models like the IIx, IIcx, and SE/30 have stock ROMs that are “dirty”, meaning they can’t support 32-bit addressing without ROM patches. Using the Mac ROM-inator II and the pre-programmed ROM image, the Mac SE/30 can support up to 128MB of RAM!

ROM Disk

The built-in ROM disk is a 5.5MB bootable disk image (12MB for the MEGA) containing System 7.1 and a collection of classic software. Using the ROM disk, it’s possible to create a diskless workstation without any physical disks attached. Once booted from the ROM disk, Appletalk file servers can also be mounted over a local network.

The ROM disk image is stored compressed in the module’s flash memory, and is decompressed on the fly as needed, in order to squeeze the largest possible disk image into the available space. This requires 1MB of RAM for caching of decompressed disk sectors, so a minimum of 2MB total system RAM is required. The ROM disk can be mounted as read-only, or as a read-write RAM disk.

Usage

When first powered on, the Macintosh will play a customized startup sound, and display diagnostic info about the amount of installed RAM, the current addressing mode, and the detected ROM disk type. After a moment, a startup menu will be displayed. To boot from the ROM disk as a read-only disk, press the R key on the keyboard. Or to convert the ROM disk into a writable RAM disk, press the A key. If no keys are pressed after five seconds, the Macintosh will boot normally from an attached SCSI disk, or wait for a floppy disk to be inserted.

If booting from a SCSI disk, any 32-bit enablers or extensions such as MODE32 or 32-Bit System Enabler must be removed from the system folder.

Programming

The Mac ROM-inator II’s flash memory can be reprogrammed using the ROM SIMM programmer, providing the ultimate in customization. There’s 4MB of flash memory (8MB for the MEGA) available for any purpose, like a custom ROM disk image, alternate ROM code, digitized sounds, user interface tweaks, or other crazy experiments. Using compression, this is enough for the base 512K ROM image plus a roughly 5.5MB uncompressed disk image (12MB for the MEGA). Or fill the whole space with a collection of different base ROMs, selected from a startup menu. Go nuts!

The programmer is a USB peripheral, and connects to your PC with a standard USB B Mini cable (not included). The programmer utility software provides an easy GUI for updating the contents of the ROM SIMM’s flash memory. The utility program is compatible with Windows 7 or later, or Mac OSX, and you can also make it work on Linux if you compile the software for yourself. It’s based on Qt and should be easily portable.

The programmer board has an integrated on/off switch for convenience. Please connect the USB cable and insert the SIMM into the socket before switching the power on. Hot-plugging the ROM SIMM or the programmer itself may cause damage.

Creating a New ROM Disk

Don’t like the contents of the default ROM disk, and want to use your own? No problem. Create a bootable HFS disk image that’s 5.5MB (12MB for the MEGA) and fill it with whatever system software and other goodies you’d like. Then use the ROM SIMM Programmer to write a modified ROM and ROM disk to the Mac ROM-inator II SIMM. See the ROM disk creation tutorial for complete details.

Advanced Hacking

Interested in alternative happy mac icons? Fancy a shot at reverse-engineering? How are your 68000 assembly skills? For true power users, all this and more is possible by patching the base ROM. Check out this ROM Hacking Tutorial for an example of modifying the startup sound behavior in the Mac’s base ROM code. Also see the linked threads and discussion at Rob Braun’s synack.net, which described the original ROM disk driver and related ROM hacks.

Get One Now

Check out the Mac ROM-inator II and ROM-inator II MEGA at the BMOW Store.

44 Comments so far

Now I want a Mac II! If I where to invest in II or IIx (IIci is so damn hard to find) what graphics card should I use?

/K

AEChadwick June 19th, 2016
6:20 pm

Hey Steve, i love your tireless work and have bought several of your products. Have you improved or streamlined Doug’s design? or are you simply the caretaker in this case, keeping the work alive? (to be clear: i have one of Doug’s ROM Simm cards and the programmer… but, you know, just give me an excuse to buy another…!!)

Both the SIMM and the programmer have changed from Doug Brown’s earlier designs, and the SIMM also now comes pre-programmed, with the on-the-fly compression disk driver that I designed. The new programmer is about 4x faster and also has an on/off switch and power LED. And it’s hexagonal. 🙂 The new programmer also works with Doug’s old SIMMs, and the old programmer will work with the new SIMMs if you update the software.

Brian Holdsworth June 23rd, 2016
10:10 am

Hi Steve. Based on your comments above, the new SIMMProgrammer.app is backwards compatible with the original dbrown SIMM and Programmer, right?

This is great news. I was running into the limit with the 8MB ROM in my IIsi and want to try out the new compression driver to see what more I can fit in there 🙂

Once I get the SE/30, I’ll add another one for that machine, because the boot speed, silent operations, and convenience are awesome.

Best.

Ben July 5th, 2016
7:18 am

Hi Steve, Mac ROM-inator II is out of stock. It will available soon ? :'(

Probably not. I believe the Daystar accelerator has its own ROM and does some kind of run-time ROM patching. If you try it, let me know what you find!

Dan Perry August 20th, 2016
11:08 am

I just got my Mac Rom-inator II in the mail and installed it in my SE/30!
Having HD20 support plus native 32-bit clean is great! It as well boots much quicker.

I am likely going to be purchasing the programmer in the near future as it would be awesome to have my OS boot directly from RAM, freeing up some space on my (miniscule) 40mb HDD.

Thanks Steve!

Todd Killingsworth November 16th, 2016
7:05 pm

I’ve finally gotten my SE/30 recapped, and put everything back together. Good news: It all works first time…. Bad news: When I replace my original ROM with the Rom-inator II, it only works when I disconnect the floppy drive. I read the manual PDF, but I didn’t see anything specific to this issue. I’ve got a new fully matched set of RAM from OWC, so I don’t think that’s the trouble. As an SE/30, there shouldn’t be a jumper to change. I’m at a loss here…. any suggestions?

Hmm, that’s strange. Have you tried pushing on the ROM SIMM while it’s booting, or using a shim, as described in the manual? Some SE/30’s seem especially picky about the ROM SIMM. If you’re unable to get it to work in your machine, you can return it for a refund, but hopefully it doesn’t come to that.

Roland December 9th, 2016
11:49 am

Dear Steve,

today I received 2 Rominator II sets. I installed them in a IIfx and a SE/30 – everything worked fine immediately ! A wonderful piece of soft- and hardware !!!

I had minor problems programming them: Mac OS Sierra was not able to communicate with the programmer (the window with progress bar saying “starting communication ,,,” stayed forever). But maybe that is an issue due to my patched Sierra on an unsupported Mac. Using Mac OS ElCapitan everything went well.

In Windows 10 your software complains about a missing plug-in “QT windows” and refuses to work.

Roland

Alden December 13th, 2016
9:15 am

Roland: I too have the “Staring Communication…” message in macOS 10.12.1 Sierra, but found quitting the app, then reading the ROM to a file is successful, THEN you can write to the ROMinator successfully. Annoying, but does end up working!

Steve: Not sure if anyone has customized the iisi+romdrv1.2.rom file for a Daystar Turbo 040, but I’d be interested – currently no boot chime if used with Turbo 040 installed.

Thanks for the macOS Sierra software work-around. I’m interested to hear if others have the same experience. As for the Daystar 040 accelerator, I believe it has its own on-board ROM, which tries to patch sections of the main ROM. Those patching attempts probably go horribly wrong when using a non-stock main ROM like ROM-inator II.

Christopher Parish January 3rd, 2017
2:38 pm

This is a super useful tool for some hardware development I’m doing with the SE/30. Two quick things:
1. The programmer doesn’t run out-of-the-box on Windows 10. I just rebuilt it in Linux (where I normally work), but others may have the same issue.
2. Do you have a listing of the offsets where the startup sound, boot icon, etc. live like the ROM-inator v1?

Thanks for the note on Windows 10. I don’t have a Win 10 system for development at the moment – looks like I’ll need to get one. I suspect the issue is with the 3rd-party library used to enumerate and talk to the USB.

So I just received my shiny new “Mac ROM-inator II” ROM stick and I’ve popped it into my SE/30. I’m able to boot from the Mac ROM-inator II’s bootable ROM/RAM disk without issue and everything seems totally normal, but when I attempt to boot to MacOS 7.5.5 from my internal SCSI drive, the system hangs at the “Welcome to Macintosh” screen. I double-checked that I don’t have Mode32 (or any other 32-bits-related control panels or extensions) enabled, and I get the same result if I hold shift down – it shows that it’s booting with extensions disabled, but still hangs at the Welcome to Macintosh screen.

Any clues here? I’ll try the obvious / easy stuff (reseat my RAM, etc.), but it just seems pretty odd to me. I’ll also try reseating / shimming the ROM stick, but given that it’s able to boot from the ROM / RAM disk, I have to assume that’s not the main issue. Thanks for any suggestions!

PS I have 64 megs of brand-new RAM arriving from OtherWorldComputing in a few days, so if this indicates a RAM issue, that will probably sort itself out shortly…

Since I have MacOS 7.5.5 on the internal drive of my SE/30, I followed that guide, changed a “0003” to a “0005” in one particular value of the system file, and the whole issue was fixed immediately. Given that this is necessary, I wish ResEdit could be included in the bootable OS found on the ROM stick – would’ve saved me some time having to shuttle ResEdit via floppy from another Mac!

I have 2 Rominator II, one for a SE/30, the other for a IIfx. Additionally I use the floppy emu, which is working fine with the SE/30 on the external port.
On the fx (without external Floppy-port) I plugged the floppy disk emu directly to the floppy-ports on the mainboard. Unfortunately the IIfx does not recognize the emulated HD20 (as the SE/30 did). Independent, which floppy-port I use on the IIfx.
Any ideas how to solve the problem ??

Sorry, I wasn’t aware the IIfx lacks an external floppy port. The Apple HD20 ROM routines are designed to expect the hard drive on the second (external) floppy port only. Since the IIfx has two internal floppy ports on its internal logic board, you may have success if you try connecting the cable to the other port.

Roland January 13th, 2017
2:37 pm

unfortunately the floppy-emu is not recognized independent which port I use 🙁

Roland January 13th, 2017
2:38 pm

.. both ports are working well with the original floppy

Roland January 13th, 2017
2:51 pm

the IIfx has a 6502 CPU subsystem to handle the floppy ports – may this cause the problem ?

That sounds plausible. If the IIfx’s connection to the floppy ports works substantially differently than in other supported Mac models, then it’s likely Apple’s HD20 routines in the ROM-inator II ROM code won’t know how to handle it.

For those having problems under Windows 10 with the ROM SIMM programmer utility software, try downloading the newest version of the software from the link above. The older version was missing some required DLLs. I’ve also left the link to the old version in place for the time being, just in case the new one has any unexpected problems.

John A January 14th, 2017
6:46 pm

Great ROM!!!

As others had stated before, my SE/30 would freeze at “Welcome to Macintosh” with OS 7.5.5…

To fix this, simply go over to the guide with the resedit tweaks, and follow the instructions for OS 7.5.5, and change that value of 0003 or something like that (It says in the guide) to the 0005. Worked great for me!

One problem I had was that when I booted to a ram disk, I keep getting disk unreadable. However, that was before I edited the file…

Patrik March 20th, 2017
3:40 am

I have just bought ROM-inator II to my SE30 but can not get it to work.
With the standard ROM the se30 works but with the ROM-inator II it get zebra stripes.
I have try different RAM configurations but no differance, only zebra lines.

Try one of the methods described in the manual for bracing or shimming the SIMM in the SE/30 ROM socket. You can email me directly if you need additional help – the address is on the Contact page.

Denny Atkinson April 12th, 2017
1:18 pm

Steve,
Maybe I’m missing a step. I just installed ROM-inator II on my 32 meg SE-30 (8, 4 meg simms). It boots into 7.1 from the ROM disc, but when I get info About This Macintosh, it shows Total Memory of 32,768K, Largest Unused Block of 6,934K, and the System Software using 25,808K. If I remember correctly (thinking back 25 years or so), that’s what happens without Mode 32 installed. Isn’t the ROM-inator supposed to be addressing that or am I just misunderstanding something?

I’ve got a Floppy-Emu here and a plan to make a bootable HD20ish setup, but I want to make sure I’m not going to be running into any ROM compatibility issues.

I’d appreciate any suggestions you can offer.

Denny Atkinson April 12th, 2017
1:39 pm

Never mind.

I forgot that I had to turn on 32 bit addressing in the the memory control panel. It\’s been a long time…cut me some slack. Thanks!

Markus Wagner April 29th, 2017
2:55 am

I would like to have one but unfortunately there is no more. It should be back to buy please infomer

For certain values of “possible”, yes. 🙂 Some PowerMacs have their ROM on a removable module, so in theory you could replace it with something custom. But the hardware and software would be entirely different from the ROM-inator II.